Safety latch for hand tool

ABSTRACT

A safety latch for a hand tool is provided. According to the present invention, the safety latch serves to hold the two handles of a safety tool in proximity to one another so as to prevent the hand tool from pivoting, and thereby maintaining the hand tool in its closed position. A latching member is first connected to the first handle. The latching member is capable of moving from a disengaged position to an engaged position. Next, a receiving member is connected to the second handle. The receiving member receives the latching member in its engaged position. In this position, the handles of the hand tool are maintained in proximity such that the tool implements of the hand tool are maintained in the closed position. Finally, a biasing member is supplied to act against the latching member. The biasing member biases the latching member in its disengaged position. Operationally, the biasing member returns the latching member to its disengaged position when the handles are drawn together, thereby allowing the hand tool to be efficiently released into its open position for use.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to the art of hand tools. Morespecifically, it relates to hand tools having a safety latch feature formaintaining the hand tool in a substantially closed position.

2. Background of the Related Art

The use of hand tools in various configurations for performing differenttasks are known. For example, pliers-type tools having a pair of jawsfor gripping objects are known. Likewise, various cutting tools such asclippers, scissors, metal cutters and pruners are known. Such hand toolstypically have a pair of handles configured to be gripped by the humanhand. The handles rotate about a pivot point such that contraction ofthe handles causes the tool implements to act upon an object. In thecase of pliers, a pair of jaws acts to grip an object. In the case ofcutting tools, a pair of blades acts to cut an object.

Those skilled in the art will recognize that hand tools present a dangerof personal injury when left in the open position. In the case of apliers-type tool, an extremity such as a finger could become caughtbetween the jaws and compressed. In the case of a cutting tool, a fingeror other body portion could be cut through inadvertent contact with oneof the blades. Further, an open tool is an attractive nuisance to asmall child, inviting a child to play with the tool, resulting ininjury.

In the context of pliers, recent patents have disclosed locking devicesfor maintaining the pliers-type tool in a closed position. U.S. Pat. No.4,538,485 (issued to Saila) and U.S. Pat. No. 5,674,244 (issued toMathys) present pliers having locking features within the two handlemeans. In each case, one handle employs an arm having a serrated edge,while another handle employs a receiving member through which theserrated arm is ratcheted. Likewise, U.S. Pat. No. 5,902,015 (issued toAllcock) discloses a gripping device for holding a seatbelt inconnection with a child safety seat. The gripping tool includes a safetylatch for holding the gripping tool in a closed position.

The purpose for holding the above tools in a closed position is forgripping an object until the safety latch is released. For example, U.S.Pat. No. 5,674,244, entitled “Locking Device on A Pliers-Shaped Tool”has its primary application in surgery. (See Abstract). Essentially, thelocking device of U.S. Pat. No. 5,674,244 allows a pliers-shaped tool toserve as a selectively adjustable and releasable clamp. However, such anapplication is without utility in the context of cutting devices. Thisis because cutting tools are only functional when they reciprocateagainst an object from an open to closed position.

In the context of cutting tools, a safety latch is needed which willefficiently maintain the cutting tool in a closed position during itsunused state. Accordingly, it is an object of the present invention toprovide a safety latch for a hand tool used for cutting by which thecutting tool may be maintained in a closed position while the tool isunused.

It is a further object of the present invention to provide a safetylatch which is efficient in that it can be quickly released so as toopen the hand cutting tool for cutting operations, and can quickly resetwhen cutting operations are concluded.

Yet, a further object of the present invention in one embodiment is toprovide a safety latch which is spring biased to accommodate theefficient operation of the safety latch.

Still a further object of the present invention is to afford a safetylatch which is economical to manufacture yet sturdy enough to withstandday-to-day use.

SUMMARY OF THE INVENTION

The present invention generally discloses an apparatus for maintaining ahand tool in a closed position while in its unused state. According tothe present invention, a safety latch is provided for holding the twohandles of the safety tool in proximity to one another so as to preventthe hand tool from pivoting, and to maintain the hand tool in a closedposition.

In the present invention, a latching member is first connected to thefirst handle. The latching member is capable of moving from a disengagedposition to an engaged position.

Next, a receiving member is connected to the second handle. Thereceiving member receives the latching member in its engaged position.In this position, the handles of the hand tool are maintained in itsclosed position.

Finally, a biasing member is supplied to act against the latchingmember. The biasing member biases the latching member in its disengagedposition. Operationally, the biasing member returns the latching memberto its disengaged position when the handles are further drawn together,thereby allowing the hand tool to be released into its open position foruse. In this manner, an efficient safety latch for a hand tool isprovided.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features, advantages andobjects of the present invention are attained and can be understood indetail, a more particular description of the invention, brieflysummarized above, may be had by reference to the embodiments thereofwhich are illustrated in the appended drawings.

It is to be noted, however, that the appended drawings illustrate onlytypical embodiments of this invention, and are therefore not to beconsidered limiting of the invention's scope. The invention admits toother equally effective embodiments.

FIG. 1 is a side view of the safety latch of the present invention,incorporated into a hand tool for cutting. In this depiction, the safetylatch is in its engaged position, maintaining the pruning tool in itsclosed position.

FIG. 2 is a side view of a safety latch of the present invention, withthe safety latch disengaged from the receiving member. In thisdepiction, the safety latch is likewise incorporated into a hand toolfor cutting Because the safety latch is in its disengaged position, thecutting tool is in its open state, ready for use.

FIG. 3 is an exploded view of a latching member of the safety latch ofthe present invention. In this case, the torsion spring and the pivotingpin are removed from the latching member.

FIG. 4 depicts a perspective view of a handle, configured to receive alatching member of the safety hook of the present invention.

FIG. 5 demonstrates the handle of FIG. 4, with the latching member andbiasing member incorporated into the handle.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 illustrates one embodiment of the safety latch 10 of the presentinvention. In this figure, a safety latch 10 is incorporated into a handtool 100 used for cutting. More specifically, a safety latch 10 isincorporated into a pruner 100, typically used for cutting smallbranches of plants (not shown). However, it will become obvious to oneof ordinary skill in the art, based upon the present disclosure, thatthe safety latch 10 of the present invention would have utility in anyhand tool wherein the two handles 22 a and 22 b are biased in an openposition.

FIG. 2 more fully demonstrates the biasing action against the twohandles 22 a and 22 b. In the embodiment shown in FIG. 1 and FIG. 2, thehandle-biasing member is a spring 18. The spring 18 has first and secondopposite ends, each end being connected to a shaft portion 14 a and 14 bof the opposing handles 22 a and 22 b. In the embodiment disclosed, theopposite ends of the spring 18 are coiled about posts 24 a and 24 bwhich extrude from shaft portions 14 a and 14 b of the opposing handles22 a and 22 b. A stop member 26 a and 26 b is also fabricated into therespective posts 24 a and 24 b in order to secure the spring 18 frombecoming detached from the posts 24 a and 24 b.

In the preferred embodiment, the respective posts 24 a and 24 b areintegral to the shaft portions 14 a and 14 b of the two handles 22 a and22 b. However, those of ordinary skill in the art will understand thatthe posts 14 a and 14 b and the attached biasing spring 18 may beincorporated between the gripping portions 12 a and 12 b of the handles22 a and 22 b. As an alternative embodiment, the biasing spring 18 couldbe incorporated around the pivot pin 20, and without the use of posts.(This embodiment, and others, is not shown).

In the preferred embodiment, the safety latch 10 of the presentinvention first contains a latching member 30. The latching member 30 isshown in perspective view in FIG. 3. In this embodiment, the latchingmember 30 first contains opposite sidewalls 32. Fabricated within eachsidewall 32 is a pin through-opening 37. The pin through-openings 37receive pin 36. Sidewalls 32 may optionally include a raised or beveledportion, shown at 31 in FIG. 3. This beveled portion assists in thegripping of the latching member 30. The latching member 30 furtherincludes an end wall 35 joining sidewalls 32.

The safety latch 10 also includes a biasing member 38. In the preferredembodiment, the biasing member is a torsion spring 38. Spring 38 has twoends 34. The two respective ends 34 fit into spring through-openings 39within sidewalls 32.

Between the two ends 34 of the spring 38 are coils 39. Coils 39 receivepin 36 of the safety latch 10. Said torsion spring 38 also includes astrut portion 38′ which resides against the shaft portion 14 b of onehandle 22.

FIG. 4 depicts a handle 22 b for receiving the latching member 30 andspring 38 of the safety latch 10 of the present invention. In thepreferred embodiment, the handle 22 b includes a rib 15 b. Rib 15 b isformed integral to the shaft portion 14 b of the handle 22 b. Within therib 15 b is a rib- through opening 13 b. Rib-through opening 13 b is forreceiving pin 36, shown in FIG. 3.

Positioning of the latching member 30 and the biasing spring 38 onto thehandle 22 b is shown in FIG. 5. The latching member 30 is in itsdisengaged state in FIG. 5. In this disengaged state, the torsion spring38 pulls the latching member 30 against the inside face of the shaftportion 14 b. This positioning is shown more fully in FIG. 2.

Referring again to FIG. 1, the latching member 30 is engaged with areceiving member 34. In the preferred embodiment, receiving member 34 isalso a rib 15 a formed integral to the shaft portion 14 a of handle 22a. In the preferred embodiment, receiving member 34 defines an L-hook.However, those of ordinary skill in the art will understand that thereceiving member 34 may take various forms, including by example only aJ-hook or a releasable latch. Receiving member 34 is aligned withlatching member 30 so as to receive latching member 30 when handles 22 aand 22 b are drawn together. When joined, the latching member 30 andreceiving member 34 form a safety latch 10 which maintains the hand tool100 in a safe, closed position.

Those of ordinary skill in the art will appreciate that, in its openposition, the sharpened edge 16 c of blade 16 a is exposed when the handtool is in its open position. This, again, creates a risk of personalinjury to the user. More seriously, it creates a risk of injury to achild who sees the hand tool as a toy. By engaging the safety latch 10of the present invention, blades 16 a and 16 b are drawn together, andthe risk of injury is minimized.

In order to use the cutting tool 100 shown in FIG. 1, it is necessary todisengage the safety latch 10. This can be done by squeezing on handlegripping portions 12 a and 12 b, drawing them together. Contracting thehandles 22 a and 22 b serves to disengage the spring-tensionedconnection between the latching member 30 and the receiving member 34.Because of the biased nature of the spring-tensioned connection,releasing the connection causes the latching member 30 to snap out ofthe receiving member 34, thereby causing a more efficient release of thesafety latch 10.

While the foregoing is directed to some embodiments of the presentinvention, other and further embodiments of the invention may be devisedwithout departing from the basic scope thereof, and the scope thereof isdetermined by the claims, as follows:

What is claimed is:
 1. A safety latch for a hand tool, the hand toolhaving first and second handles for moving the hand tool about a pivotpoint from an open position to a closed position, and the hand toolbeing biased in its open position, the safety latch comprising: alatching member connected to the first handle, the latching membermoving from a disengaged position to an engaged position; a biasingmember for biasing the latching member in its disengaged position; and ahook connected to the second handle for receiving the latching member inits engaged position, whereby the hand tool is maintained in its closedposition when the latching member is engaged with the receiving member;wherein the latching member comprises: a pin about which the latchingmember pivots from its disengaged position to its engaged position;first and second opposite side walls, each of the first and secondopposite side walls having a proximal end and a distal end, and each ofthe first and second opposite side walls having a pin through-opening atthe proximal end for receiving the pin; and an end wall connected to thefirst and second opposite side walls at the respective distal ends, theend wall configured to be received by the hook when the latching memberis in its engaged position; and wherein each of the first and secondhandles of the hand tool includes a gripping portion distal to the pivotpoint of the hand tool, and a shaft portion proximal to the pivot pointof the hand tool, the latching member being connected to the firsthandle of the hand tool at the shaft portion of the first handle, andthe hook being connected to the second handle of the hand tool at theshaft portion of the second handle.
 2. The safety latch of claim 1,wherein the hand tool is biased in its open position by means of aspring positioned between the first and second handles, the springhaving a first end and a second end.
 3. The safety latch of claim 2,wherein each of the shaft portions of the first and said second handlesincludes a post, the post of the shaft portion of the first handlereceiving the first end of the spring, and the post of the shaft portionof the second handle receiving the second end of the spring.
 4. Thesafety latch of claim 3, wherein: the shaft portion of the first handleincludes a through-opening also configured to receive the pin; and thelatching member is connected to the shaft portion of the first handle bymeans of the pin.
 5. The safety latch of claim 4, wherein the biasingmember of the safety latch defines a spring, the spring comprising afirst end; a second end; at least one coiled portion between the firstend and the second end of the spring, the coiled portion residing aroundthe pin; and wherein the first and second opposite side walls of thelatching member further each include a spring through-opening wherebythe first end of the spring is received within the springthrough-opening of the first side wall of the latching member, and thesecond spring is received within the spring through-opening of thesecond side wall of the latching member.
 6. The safety latch of claim 5,wherein the spring is tensioned so as to bias the latching member suchthat the end wall of the latching member is oriented towards thegripping portion of the first handle when the latching member is in itsdisengaged position, and wherein the spring includes: a first coilproximal to the first side wall of the latching member; a second coilproximal to the second side wall of the latching member; and wherein thespring further includes a strut portion between the first coil and thesecond coil of the spring, the strut portion being retained proximal tothe first handle of the hand tool.
 7. The safety latch of claim 6,wherein at least one of each of the first and second opposite side wallsof the latching member further includes a beveled portion to facilitatemanipulation of the latching member from its disengaged position to itsengaged position.
 8. The safety latch of claim 4, wherein the hand toolis a cutting instrument.
 9. The safety latch of claim 8, wherein thecutting instrument is a pruner.
 10. The safety latch of claim 4, whereinthe hand tool is a pliers-type tool.
 11. A safety latch for a hand tool,the hand tool having first and second handles for moving the hand toolabout a pivot point from an open position to a closed position, and thehand tool being biased in its open position by means of a springpositioned between the first and second handles, the safety latchcomprising: a latching member connected to the first handle, thelatching member moving from a disengaged position to an engagedposition, the latching member comprising: first and second opposite sidewalls, each of the first and second opposite side walls having aproximal end and a distal end, and each of the first and second oppositeside walls having a pin through-opening at the proximal end forreceiving a pin; a pin about which said latching member pivots from itsdisengaged position to its engaged position; and an end wall connectedto the first and second opposite side walls at the respective distalends, the end wall configured to be received by the hook when thelatching member is in its engaged position; a biasing member for biasingthe latching member in said disengaged position; a receiving memberconnected to the second handle for receiving the latching member in itsengaged position, the receiving member defining a hook, whereby the handtool is maintained in its closed position when the latching member isengaged with the hook.
 12. The safety latch of claim 11, wherein each ofthe first and second handles of the hand tool includes a grippingportion distal to the pivot point of the hand tool, and a shaft portionproximal to the pivot point of the hand tool; the latching member beingconnected to the first handle of the hand tool at the shaft portion ofthe first handle; and the receiving member being connected to the secondhandle of the hand tool at the shaft portion of the second handle. 13.The safety latch of claim 12, wherein the shaft portion of the firsthandle includes a through-opening also configured to receive the pin;and the latching member is connected to the shaft portion of the firsthandle by means of the pin.
 14. The safety latch of claim 13 whereinsaid biasing member of said safety latch defines a spring, said springcomprising a first end; a second end; at least one coiled portionbetween said first end and said second end of said spring, said coiledportion residing around said pin; and wherein said first and secondopposite side walls of said latching member further each include aspring through-opening whereby said first end of said spring is receivedwithin said spring through-opening of said first side wall of saidlatching member, and said second spring is received within said springthrough-opening of said second side wall of said latching member. 15.The safety latch of claim 14 wherein said spring is tensioned so as tobias said latching member such that said end wall of said latchingmember is oriented towards the first handle when said latching member isin said disengaged position, and wherein at least one coiled portion ofsaid spring includes a first coil proximal to said first side wall ofsaid latching member; a second coil proximal to said second side wall ofsaid latching member; and wherein said spring further includes a strutportion between said first coil and said second coil, said strut portionbeing retained proximal to the first handle of the hand tool.
 16. Thesafety latch of claim 15 wherein said cutting instrument is a pruner.17. A safety latch for a hand tool, the hand tool having first andsecond handles for moving the hand tool about a pivot point from an openposition to a closed position, the first handle having a pinthrough-opening, the safety latch comprising: a latching memberconnected to the first handle, said latching member moving from adisengaged position to an engaged position, and said latching membercomprising first and second opposite side walls, each of said first andsecond opposite walls having a proximal end and a distal end, and eachof said first and second opposite walls having a pin through-opening atsaid proximal end; a pin received within the pin through-opening of thefirst handle; an end wall connected to said first and second oppositewalls at said respective distal ends, said end wall configured to bereceived by said receiving member; and wherein said pin through-openingsof said first and second opposite side walls are configured to receivesaid pin about which said latching member rotates from said disengagedposition to said engaged position; a biasing member for biasing saidlatching member in said disengaged position, said biasing memberdefining a spring comprising a first end; a second end; at least onecoiled portion between said first end and said second end of saidspring, said coiled portion residing around said pin; and a first coilproximal to said first said wall of said latching member for receivingsaid pin; a second coil proximal to said second side wall at saidlatching member also for receiving said pin; a strut portion betweensaid first coil and said second coil, said strut portion being retainedproximal to the first handle of the hand tool; wherein said first andsecond opposite side walls of said latching member further each includea spring through-opening whereby said first end of said spring isreceived within said spring through-opening of said first side wall ofsaid latching member, and said second spring is received within saidspring through-opening of said second side wall of said latching member;and said spring being tensioned so as to bias said latching member suchthat said end wall of said latching member is oriented towards the firsthandle when said latching member is in said disengaged position; areceiving member connected to the second handle for receiving saidlatching member in said engaged position, whereby the hand tool ismaintained in its closed position when said latching member is engagedwith said receiving member, said receiving member defining a hook; andwherein said hand tool is biased in its open position by means of aspring positioned between said first and second handles, said springhaving a first end connected to the first handle and a second endconnected to the second handle.